diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-04-03 07:06:53 -0500 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-04-03 07:06:53 -0500 |
commit | 7b367f5dba5c5162a7308e85d3fc9170b0cb3e5f (patch) | |
tree | a93a93e01dcb4203d545ef61edcb5c4236b49ded /kernel/locking/lockdep.c | |
parent | 17084b7e07909d3a8d51b66b7dfb50a2083a2685 (diff) | |
parent | 353def94606fda16d9ae1761b4b0583286481ec5 (diff) |
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core kernel fixes from Ingo Molnar:
"This contains the nohz/atomic cleanup/fix for the fetch_or() ugliness
you noted during the original nohz pull request, plus there's also
misc fixes:
- fix liblockdep build bug
- fix uapi header build bug
- print more lockdep hash collision info to help debug recent reports
of hash collisions
- update MAINTAINERS email address"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
MAINTAINERS: Update my email address
locking/lockdep: Print chain_key collision information
uapi/linux/stddef.h: Provide __always_inline to userspace headers
tools/lib/lockdep: Fix unsupported 'basename -s' in run_tests.sh
locking/atomic, sched: Unexport fetch_or()
timers/nohz: Convert tick dependency mask to atomic_t
locking/atomic: Introduce atomic_fetch_or()
Diffstat (limited to 'kernel/locking/lockdep.c')
-rw-r--r-- | kernel/locking/lockdep.c | 79 |
1 files changed, 77 insertions, 2 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 53ab2f85d77e..2324ba5310db 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2000,6 +2000,77 @@ static inline int get_first_held_lock(struct task_struct *curr, } /* + * Returns the next chain_key iteration + */ +static u64 print_chain_key_iteration(int class_idx, u64 chain_key) +{ + u64 new_chain_key = iterate_chain_key(chain_key, class_idx); + + printk(" class_idx:%d -> chain_key:%016Lx", + class_idx, + (unsigned long long)new_chain_key); + return new_chain_key; +} + +static void +print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) +{ + struct held_lock *hlock; + u64 chain_key = 0; + int depth = curr->lockdep_depth; + int i; + + printk("depth: %u\n", depth + 1); + for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) { + hlock = curr->held_locks + i; + chain_key = print_chain_key_iteration(hlock->class_idx, chain_key); + + print_lock(hlock); + } + + print_chain_key_iteration(hlock_next->class_idx, chain_key); + print_lock(hlock_next); +} + +static void print_chain_keys_chain(struct lock_chain *chain) +{ + int i; + u64 chain_key = 0; + int class_id; + + printk("depth: %u\n", chain->depth); + for (i = 0; i < chain->depth; i++) { + class_id = chain_hlocks[chain->base + i]; + chain_key = print_chain_key_iteration(class_id + 1, chain_key); + + print_lock_name(lock_classes + class_id); + printk("\n"); + } +} + +static void print_collision(struct task_struct *curr, + struct held_lock *hlock_next, + struct lock_chain *chain) +{ + printk("\n"); + printk("======================\n"); + printk("[chain_key collision ]\n"); + print_kernel_ident(); + printk("----------------------\n"); + printk("%s/%d: ", current->comm, task_pid_nr(current)); + printk("Hash chain already cached but the contents don't match!\n"); + + printk("Held locks:"); + print_chain_keys_held_locks(curr, hlock_next); + + printk("Locks in cached chain:"); + print_chain_keys_chain(chain); + + printk("\nstack backtrace:\n"); + dump_stack(); +} + +/* * Checks whether the chain and the current held locks are consistent * in depth and also in content. If they are not it most likely means * that there was a collision during the calculation of the chain_key. @@ -2014,14 +2085,18 @@ static int check_no_collision(struct task_struct *curr, i = get_first_held_lock(curr, hlock); - if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) + if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) { + print_collision(curr, hlock, chain); return 0; + } for (j = 0; j < chain->depth - 1; j++, i++) { id = curr->held_locks[i].class_idx - 1; - if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) + if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) { + print_collision(curr, hlock, chain); return 0; + } } #endif return 1; |